Here are some of my favorites I have found thus far:

• Web Developer’s Toolbox
  12 add-ons to help you speed up the development process when it comes to web development and managing the ins and outs of your own web site.
• Downloadsquad Pack
  Soup up your browser with selections from the Downloadsquad.com staff and some of our readers’ favorite add-ons. They’ll help make your browsing safer, more hassle free, and more productive!
• Traveler’s Pack
  When the travel bug bites, these add-ons make it easy to plan, book and document your trip — without getting lost along the way.

That is just a small sample of what is out there, and who know – I might be working on a Firefox Facts Pack in the near future.  Creating your own pack is easy to do.  All you have to do is login to the addons.mozilla.org web site, and then visit the create a collection page.  From there, you give it a name, description, decide if you want your pack to be public or private, then start naming off your add-ons that will be included. 

What have been your favorite add-on collections, so far?

Thanks Yahoo, I am sure Mozilla and the Firefox team appreciates the support!